Purpose The purpose of this research is to scrutinize numerically the effect of internally equipped nonuniformly heated plate within wavy cavity on heat transfer enhancement in the case of hybrid nanofluid flow. Design/methodology/approach The two-dimensional, steady, laminar, Newtonian and incompressible thermo-fluid flow phenomenon has been investigated numerically using Galerkin method. The considered parameters including number of waves (3–7), nondimensional length of heated plate (0.4–0.8), plate inclination angle (0º–90º), Rayleigh number (103–106) and concentration of nanoparticles (0.0–2.0) have been investigated in combination with involving hybrid nanofluid as a working fluid to augment thermal properties effectively. Two vertical wavy boundaries have low temperature whilst the other horizontal surfaces are adiabatic. Findings The Rayleigh number has a moderate impact on the values of Nusselt number, and skin friction parameter varied from 103 to 105 while it strongly affects them for Ra = 106, where Nu is roughly doubled (approximately 200%) in comparison with its value at Ra = 105 for all cases. Stream function is changed by the orientation of heated plate and Ra values, where its maximum value was 12.9 in horizontal position and 13.6 at vertical one. Results indicate a separation from the wavy walls at low Ra which tends to keep stagnation region at the deep parts of corrugated walls contrary the case at high Ra. The behavior of the isotherm contours tends to be distributed more evenly at lower values of Ra and angle of inclination lower than 45º. The resulting properties from mixing two materials for hybrid nanofluid into one base fluid show a good compromise between thermal capacity and heat conductivity, which is improved by 16% that leads to enhanced convective energy transport in the wavy chamber. Originality/value The originality of this work is the considered physical phenomenon where an influence of internal nonuniformly heated plate has been studied for the irregular geometry filled with a hybrid nanofluid. Such analysis allows defining the possible heat transfer enhancement for such an irregular cavity and inner heated plate.
Great attention is directed towards the study of the spray phenomena theoretically and experimentally due to its dramatic effect on the combustion process that occurred in an internal combustion engine, in particular, the diesel engine. The spray macroscopic characteristic of diesel engines fueled with two different biodiesel fuels in addition to nominal diesel under various injection pressures has been investigated numerically in this work. The selected biofuels are Rapeseed methyl ester (RME), Waste cooking oil methyl ester (WCOME). The Russian simulation software Diesel-RK is used in this work. Four different injection pressures are used which are 200, 500, 800 and 1000 bar respectively. It is found that RME has higher spray penetration with a narrow spray angle due to high viscosity and large momentum compared to diesel fuel. The results reported that biodiesels have greater Sauter mean diameter (SMD) compared to pure diesel because of their higher viscosity and surface tension. Promising reduction in SMD comes with WCOME as the injection pressure increases. Cylinder pressure along with heat release is reduced in the case of biodiesel due to the reduction in heating values. The lowest ability to produce smoke is recorded for WCOME where 93% reduction is achieved followed by a 57% reduction for RME as compared to diesel. The obtained results are compared with the results of other researcher and the convergence between them is observed.
Numerical study of natural convective heat transfer of partially heated tall rectangular cavity filled with (Al2O3-water) nanofluid. Two opposing horizontal walls are adiabatic, while the right vertical wall is kept at fixed cold temperature, and the left wall of the cavity heated partially. The effect of Rayleigh number (Ra), Aspect ratio (A), and the volume fractions of nanoparticles (ϕ) on the isotherms, streamline, and the average Nusselt number (Nu) have been investigated. The dimensionless governing equations with the Boussinesq approximation have been solved numerically, by using the finite element approach. The results presented for a wide range of parameters including; (103≤Ra≤105, 5≤A≤10, and 0.02≤ϕ≤0.06). The result shows that; the Nu increase when the effect of Rayleigh number (Ra), and the volume fractions of nanoparticles (ϕ) increasing, and also it increase when the Aspect ratio (A) increasing.
In this study, numerical computations of the influence of adding ribs in a rectangular channel on the forced convection heat transfer and laminar fluid flow characteristics has been carried out. The analysis was carried out by using the finite element method to solve the dimensionless governing equations for two-dimensional channel with 80 mm height and 2000 mm length at the Reynolds number of (10, 100, and 500), rib height e=8mm with different aspect ratios (AR =2.5, 3.125, 3.75, 4.375, and 5). Also, the study compared two cases of investigations with and without nanofluid (Water/ TiO2) at the volume fractions of nanoparticles of 0, 2 and 4%. The results concluded that, for a certain arrangements, the use of extended surfaces within a rectangular channel can significantly enhance the rate of heat transfer and when the aspect ratios decreases, the Nusselt number increased. However, the existence of ribs within channel in case of constant heat flux can cause a significant improvement of heat transfer compared to that in the corresponding channel under the variable heat flux.
The objective of this review is to provide a deep overview of liquid biofuels produced from sugarcane bagasse and to address the economic challenges of an ethanol and acetone-butanol-ethanol blend in commercial processes. The chemistry of sugarcane bagasse is presented. Pretreatment technologies such as physical, chemical pretreatment, biological, and combination pretreatments used in the fermentation process are also provided and summarised. Different types of anaerobic bacteria Clostridia (yeast) are discussed to identify the ingredient best suited for sugarcane bagasse, which can assist the industry in commercializing ethanol and acetone-butanol-ethanol biofuel from biomass sugarcane. The use of an acetone-butanol-ethanol mixture and ethanol blend in internal combustion engines is also discussed. The literature then supports the proposal of the best operating conditions for fermentation to enhance ethanol and acetone-butanol-ethanol plant efficiency in the sugar waste industry and its application in internal combustion engines.
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